Initialize create_disposition to FILE_OPEN in sandbox

sandbox/win/src/filesystem_dispatcher.cc

 // Copyright (c) 2006-2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sandbox/win/src/filesystem_dispatcher.h"
 
 #include "sandbox/win/src/crosscall_client.h"
 #include "sandbox/win/src/filesystem_interception.h"
 #include "sandbox/win/src/filesystem_policy.h"
 #include "sandbox/win/src/interception.h"
@@ skipping 127 matching lines @@
                                       uint32 open_options) {
   if (!PreProcessName(*name, name)) {
     // The path requested might contain a reparse point.
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
   }
 
   const wchar_t* filename = name->c_str();
 
   uint32 broker = TRUE;
-  uint32 create_disposition = 0;
+  uint32 create_disposition = FILE_OPEN;
   CountedParameterSet<OpenFile> params;
   params[OpenFile::NAME] = ParamPickerMake(filename);
   params[OpenFile::ACCESS] = ParamPickerMake(desired_access);
   params[OpenFile::DISPOSITION] = ParamPickerMake(create_disposition);
   params[OpenFile::OPTIONS] = ParamPickerMake(open_options);
   params[OpenFile::BROKER] = ParamPickerMake(broker);
 
   // To evaluate the policy we need to call back to the policy object. We
   // are just middlemen in the operation since is the FileSystemPolicy which
   // knows what to do.
@@ skipping 146 matching lines @@
     ipc->return_info.nt_status = STATUS_ACCESS_DENIED;
     return true;
   }
 
   // Return operation status on the IPC.
   ipc->return_info.nt_status = nt_status;
   return true;
 }
 
 }  // namespace sandbox